One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,7)(4,6)(5,8)(9,10,15,24,14,19,11,16)(12,22,20,17,13,23,21,18)(27,33)(30,39)(34,40)(35,38)(1,3)(2,5)(4,8)(6,7)(9,11,14,15)(10,16,19,24)(12,20,13,21)(17,23,18,22)(25,26,28,31)(27,34,33,40)(29,37,36,32)(30,38,39,35)(9,12,14,13)(10,17,19,18)(11,20,15,21)(16,23,24,22)(25,27,28,33)(26,30,31,39)(29,38,36,35)(32,40,37,34)(2,6)(3,8)(9,13,14,12)(10,18,19,17)(11,21,15,20)(16,22,24,23)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.